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Kefir, Remarkable Food
Written by: Dr. Ted Farnworth, Ph. D., Senior Scientist, Food Research and Development Centre and Agri-Food Canada, St-Hyacinthe, Québec
A bit of history:
The history of kefir extends back before writing. In ancient times the nomads carried milk of goats, sheep and other animals in skin bags as they travelled about. The fermentation that occurred in the bags turned the milk to a thick drink with a unique taste that we know to-day as kefir. At the same time the bacteria and yeast in the bag combined with milk proteins to form a mass of living growing micro-organisms that could be used to innoculate a new batch of milk to produce more kefir. This mass of bacteria / yeasts / and polysaccharides is called kefir gain and it is the grains that give kefir its unique taste and properties.
Over the centuries the grains have been handed down from person to person. The grains were only entrusted to someone who understood that the kefir grains had to be nurtured and cared for. It is generally agreed that the best defined source of kefir grains is Russia. Other countries also make kefir, but it is not known whether at some point in time they all originated from one source of grains. To produce true kefir, a true source of kefir grains must be used.
Kefir Grains:
Kefir grains are irregular in shape, is some ways resemble cauliflower florets. They are pale yellow / white in colour and have a texture similar to tapioca pudding. Live growing and reproducing bacteria and yeasts are imbedded in a matrix of polysaccharides and milk proteins that make up the kefir grains.
Microbiologists have studied the grains to better understand what they are, how they grow and reproduce and how they ferment milk. Kefir grains from different parts of the world might have different mixtures of bacteria and yeast. Over 20 types of bacteria have been identified in kefir gains including: Lactobacillus brevis, Lb. kefir, Lb. kefiranofaciens, Lactococcus lactis, and Leuconostoc spp. Various types of yeast have also been found in kefir grains such as Candida kefir, Kluyveromyces marxianus and Saccharomyces cerevisiae.
At the present time it is not clear what factors affect the amounts of a particular bacteria or yeast in kefir grains or what is the contribution of an individual bacterial strain to the properties of the final fermented product. It may well be that kefir's unique taste, texture and health benefits are the result of the interactions of all the different bacteria, yeasts and the polysaccharide in kefir grains. These complex interactions are not fully understood at this time and are very difficult to reproduce in the laboratory.
Kefir grains contain live bacteria and yeasts. After the fermentation process, the final product contains enough live bacteria and yeasts to be considered as a probiotic. Many consumers are looking to add probiotic products to their diet, because of growing evidence that the consumption of live bacteria may be beneficial to health.
Some kefir manufacturers produce a fermented milk made from a selected number of well defined bacteria rather than from true grains. Such products obviously lack the complexity of that produced from true grains and the taste, texture and nutritional properties of such "kefirs" is different from kefir produced from authentic grains.
Productions and Health Benefits | 
